My VMI fuel probes failes when the spacers on the anode slid down and allowed the anode to touch the cathode. Since the circuit has proven to be unreliable. I got Princeton probes from the inventor/distributor/sales : Todd.
ISSUES:
The VMI probe is 1/2" diameter as are the existing holes in the two ribs that hold the probe. The EI probe is 3/4" and will not fit the holes, at least not on mine. The Princeton probe is only 1/4" OD.
The Princeton probe (616-245-7700 x233) is superior to the VMI probe in every way, except, the 1/4" diameter leaves it vulnerable to bending when under load such as turbulence, coupled with a nearly empty tank.
Thus, I reused the old 1/2" outer tube from the VMI as a "carrier tube." I reused the old VMI spacers after drilling out the hole to fit over the 1/4" Princeton probe and reduced the OD a bit to allow fuel to flow easily within the 1/2" tube. Plus, I ran some tests on the spacers and found they put off a cloud of contamination in 100LL, therefore, I coated the spacers with a thin coat of Hysol (Proseal just as good).
Tricky part! When making a carrier tube out of the old 1/2" VMI probe, the small hole near the bottom of the Princeton probe MUST BE exposed to the fuel unrestricted by being covered by the carrier tube!! Or you will get to do it over a 2nd time like me.
Tricky part #2! Tell Todd at Princeton that you want the 48" probe with only ONE set point (empty). He knows why and can explain it to you, basically, it reduces the need to fuel/defuel/fuel in the calibration process. It is simply just going to give you a linear fuel read.
Shaping of the carrier tube:
The Princeton probe should stick out several inches past the end of the carrier tube.
The carrier tube can be shaped to a curvature at the sensor "puck" to allow the tube to dip down a bit before it starts back up hill. With careful use of the dremel, you can allow for the carrier tube to have a bit of a collar around the puck terminus and yet still dremel out enough material off the bottom of the of the carrier tube to expose the small hole at the bottom of the Princeton probe. Again, it's critical that the small hole is NOT covered by the al of the carrier tube.
Each Princeton probe is somewhat custom made, and I asked that the bendable portion of the Princeton probe be fairly short, about 3", to allow the small hole of the Princeton probe to be as low in the tank as possible, given that the geometry was already dictated by the probe placement angle at the opening as well as the holes in the ribs.
Jack Addison jraddison@msn.com
360 MK 2